Progresses in wearable technology have been quite mindblowing as of late but they pale in comparison to the one described in a new Nature study. The device in focus shines a poor light on the Apple Watch now decked out with an FDA-approved EKG sensor and Samsung’s smartwatches proving to be fashion statements, as remarked in the paper which was published on Wednesday. This heart-sensor is wireless, demands no battery refuelling and is so compact that it can be placed over a rat’s heart.

Study co-author Kenjiro Fukuda, Ph.D., a research scientist at Japan’s RIKEN Center for Emergent Matter Science is swift to remark that his device is a huge leap for wearables. It seems like a bandaid more than a watch and is thinner than a piece of cardboard.
“We expect long-term monitoring of the heartbeat with minimum discomfort when the devices are attached to the human body,” he tells Inverse. “[Its] flexibility and lightweight can reduce the discomfort when the devices are attached to a human body.”
A Device You Can Flex With
The device is no more powerful than any other already present heart-sensing technology, however, it does have an edge over them in terms of flexibility which has been a burning issue with smartwatch trackers. Since human bodies move in usual and arbitrary ways the devices that detect heart rate on the wrist are likely to be confounded due to awkward motions.
“Such ultra-thin devices enable better conformability than conventional wearable devices such as a smart-watch,” he says. “This can lead to better and more stable monitoring than such conventional devices.”
In early tests performed by the team where they were successful in wrapping the device around a rat’s heart, the device stuck tightly to the slimy, round surface of the rat’s chest cavity. Overlooking the uneven beating of the rat’s stressed-out heart, the test concluded, the device was able to record each heartbeat accurately and then send that data to an outer device. This would not have been possible even with an efficient chest wrap heart rate monitor.

Solving the Solar Problem
The groundbreaking characteristic of this device is in the way that it is powered. It has minute organic solar cells that convert light into electricity. The thought behind the project was to create a green, self-sustaining wearable that does not require being taken off.
Developing solar-powered technology comes with technical difficulties for researchers, says Fukuda, because it is not easy to be assured that those important solar cells are getting the fair amount of sunlight during events where a person is bending, flexing or changing frequently the angle of the device to that of a light source.
However, this problem was tackled quite easily by Fukuda’s device. He made a “nano-grating” surface on parts of the solar cells that take in light. The effects of odd, indirect angles on the cell’s absorption were subsequently diminished through these tiny rough surfaces. Fukuda takes liberty in saying that the technique in question allows for “light angle independence” in the solar cells.
Such devices including those under development at Fukuda’s lab are supposed to camouflage with the skin rather than being fashion statements. The device still has a long way to be up to medical standards despite seeming flawless. Yet, Fukuda is full of hope.
“Our devices don’t expect more precise monitoring than conventional ECG monitoring device used as a medical checkup,” he says. “If accuracy is further improved, this can be also used as imperceptible electrocardiogram systems for healthcare/medical use.”